منابع مشابه
The failure of cosmological perturbation theory in the new ekpyrotic and cyclic ekpyrotic scenarios
Cosmological perturbation theory fails in the new ekpyrotic and cyclic ekpyrotic scenarios, before the scale factor of the Universe reaches zero. As a result, these scenarios do not provide a mechanism for generating the observed curvature perturbation at the bounce. Introduction It is now clear that the dominant cause of large-scale structure in the Universe is a perturbation in the spatial cu...
متن کاملEkpyrotic and Cyclic Cosmology
Ekpyrotic and cyclic cosmologies provide theories of the very early and of the very late universe. In these models, the big bang is described as a collision of branes and thus the big bang is not the beginning of time. Before the big bang, there is an ekpyrotic phase with equation of state w = ρ ≫ 1 (where P is the average pressure and ρ the average energy density) during which the universe slo...
متن کاملNew Ekpyrotic Cosmology
In this paper, we present a new scenario of the early Universe that contains a pre big bang Ekpyrotic phase. By combining this with a ghost condensate, the theory explicitly violates the null energy condition without developing any ghost-like instabilities. Thus the contracting universe goes through a non-singular bounce and evolves smoothly into the expanding post big bang phase. The curvature...
متن کاملConfronting Particle Emission Scenarios with Strangeness Data
We show that a hadron gas model with continuous particle emission instead of freeze-out may solve some of the problems (high values of the freeze-out density and specific net charge) that one encounters in the latter case when studying strange particle ratios such as those from the experiment WA85. This underlines the necessity to understand better particle emission in hydrodynamics to be able ...
متن کاملParton Production Scenarios B + G
Initially an ultrarelativistic heavy-ion collision is gluon dominated to a degree that these bosons can be described as a classical vector potential A. The question is now, whether the production of quark-antiquark pairs or the production of quantum gluons from the eld dominates. In the background eld method of quantum chromodynamics a classical gauge eld and quantum uctuations are treated at t...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Cosmology and Astroparticle Physics
سال: 2016
ISSN: 1475-7516
DOI: 10.1088/1475-7516/2016/11/024